One of the headlines in President Obama's January 24, 2012, State of the Union address was his declaration that he would work to disclose the ingredients in the "fracking" fluids pumped at high pressure into shale formations to release natural gas. Residents of some states have complained that fracking fluids contain toxic chemicals that are contaminating their drinking water wells.

For years, the problem has been the "Halliburton amendment" to the 2005 Energy Policy Act. At the urging of former Halliburton exec Dick Cheney's Energy Policy Task Force, the 2005 law exempted the production method known as hydrofracturing from most requirements of the Safe Drinking Water Act (which normally authorizes the government to require disclosure of substances injected into underground wells). So when it comes to disclosure of what's in fracking fluids, the federal government's hands are mostly tied.

Most current fracking operations happen on non-federal lands. But on federal lands (which Obama vowed to open up to fracking in his State of the Union address), things are different. Obama vowed to require disclosure of fluids as a condition of new leases for fracking on federal lands. If it takes place, this could push the ingredient lists further into the open.

Some states where fracking is booming are already well ahead of the federal government on fracking-fluid disclosure. They include Texas, Colorado, Pennsylvania, Arkansas, Montana, and Wyoming — although in some of the states the disclosure is less than complete.